import React, { Component } from 'react'
// 引入store，用于获取redux中保存状态
import store from '../../redux/store'
// 引入actionCreator，专门用于创建action对象
import { createIncrementAction, createDecementAction } from '../../redux/count_action'

export default class Count extends Component {
	
	// componentDidMount() {
	// 	// 检测redux中状态的变化，只要变化，就调用render
	// 	store.subscribe(() => {
	// 		this.setState({}) // 利用setState触发render，但是会有效率上的问题
	// 	})
	// }

	//加法
	increment = ()=>{
		const {value} = this.selectNumber
		store.dispatch(createIncrementAction(value * 1))
	}
	//减法
	decrement = ()=>{
		const {value} = this.selectNumber
		store.dispatch(createDecementAction(value * 1))
	}
	//奇数再加
	incrementIfOdd = ()=>{
		const {value} = this.selectNumber
		const count = store.getState()
		if(count % 2 !== 0){
			store.dispatch(createIncrementAction(value * 1))
		}
	}
	//异步加
	incrementAsync = ()=>{
		const {value} = this.selectNumber
		setTimeout(()=>{
			store.dispatch(createIncrementAction(value * 1))
		},500)
	}

	render() {
		return (
			<div>
				<h1>当前求和为：{store.getState()}</h1>
				<select ref={c => this.selectNumber = c}>
					<option value="1">1</option>
					<option value="2">2</option>
					<option value="3">3</option>
				</select>&nbsp;
				<button onClick={this.increment}>+</button>&nbsp;
				<button onClick={this.decrement}>-</button>&nbsp;
				<button onClick={this.incrementIfOdd}>当前求和为奇数再加</button>&nbsp;
				<button onClick={this.incrementAsync}>异步加</button>&nbsp;
			</div>
		)
	}
}
